Core-A: Import CMSIS-Core(A)

This commit imports the CMSIS-Core(A) from the upstream CMSIS 5.6.0
release, in preparation for the AArch32 Cortex-A architecture support
in Zephyr.

Origin: CMSIS_5
License: Apache-2.0
URL: https://github.com/ARM-software/CMSIS_5/tree/5.6.0


commit: b5f0603d6a584d1724d952fd8b0737458b90d62b
Purpose: Provide a hardware interface to the Arm Cortex-A architecture
Maintained-by: External

Signed-off-by: Stephanos Ioannidis <root@stephanos.io>